Continuous-time delta-sigma modulators continue to be researched and are included in various communication products. One variable affecting performance of a delta-sigma modulator is delay. As such various techniques continue to be developed to improve delay compensation within delta-sigma modulators.
An example of a known delay compensation technique applicable to a delta-sigma modulator is described in the article titled “A Robust STF 6 mW CT ΔΣ Modulator with 76 dB Dynamic Range and 5 MHz Bandwidth” by Ranjbar et al., which appears in the Custom Integrated Circuits Conference (CICC), 2010 IEEE conducted on Sep. 19-22, 2010. The article describes that providing a direct feedback path (i.e., local feedback path) between a last integrator stage and quantizer represents a classical solution for compensation of excess loop delay within a continuous-time delta-sigma modulator. In addition, the article describes compensating for delay of a preamplifier within a quantizer that would contribute to delay of the local feedback loop by providing a delay replica signal to a latch signal of a comparator within the quantizer.
However, as communication products and techniques continue to develop, improved delay compensation techniques are desired and/or required.